Pusher mechanism for floating tank roof seals



Sept. 12, 1950 J. H. WIGGINS PUSHER MECHANISM FOR FLOATING TANK ROOF SEALS Filed April 26, 1945 2 Sheets-Sheet 1 JOHN H. WIGG/NS ATTORNEY Sept. 12, 1950 J. H- WIGGINS PUSHER MECHANISM FOR FLOATING TANK ROOF SEALS Filed April 26, 1945 2 Sheets-Sheet 2 JOHN H. WIGGINS BY WW ATTORNEY Patented Sept. 12,1950

ROOF SEALS Y PUSHER, MECHANISM FOR FLOATING TANK i mm H. Wiggins, triage,- 111.] Application April 26, 1945, Serial No. 590,475

2Claims. 1 i

This invention consists of a pusher mechanism for holding afloating tank roof side wall seal in sliding engagement with the tank side wall with which said seal co-acts. It is similar in general design and in principle of operation to the pusher mechanism described in my prior U. S. Patent No. 2,287,211, dated June 23, 1942.

One object of my present invention is toprovide a pusher mechanism of the general type or .kind disclosed in my said prior patent, that is efficient, inexpensive to construct, and easy to install.

Another object is to provide a pusher mechanism for a side wall seal, that comprises springactuated, rockable actuating devices on a floating roof, so constructed and arranged that the thrust or pressure produced by said devices on the side wall seal has no tendency to cause said side wall seal to move circumferentially away from the position said side wall seal naturally assumes. j

And still another object is to provide a-pusher mechanism of the general type disclosed in my said prior patent, in which the rockable actuating devices of the mechanism are of such design and are mounted on the floating roof in such a manner, that it is a relatively simple matter to effectively seal or render gas-tight the joints or bearings between said'actuating devices and the floating roof onwhich said devices are mounted. Other objects and desirable features of my invention will be hereinafter pointed-out.

Figure 1 of the drawings is a fragmentary vertical sectionalview, illustrating the pusher mechanism embodying my present invention.

Figure 2 is a view of one of the rockable actuating devices and the presser bar with which it co-acts, looking outwardly from the center of the floating roof towards the tank side wall, the side wall shoe being omitted, but showing the flexible sealing member that is attached to the side wall shoe and to the peripheral edge of the floating roof.

Figure 3 is a top plan view'of one of the presser bars and the two pivotally mounted members on said presser bar that bear against the side wall shoe.

Figure 4 is afragmentary top plan view, on an enlarged scale, partly in horizontal section, illustrating one of the rockable actuating devices and the presser bar associated with said actuat ing device; and

Figure 5 is an enlarged fragmentary side elevational view ofthe lower end portion of one of the rockable actuating devices and the presser bar with which it co-acts, illustrating the various positions assumed by said parts when they are performing their function. 1

My: invention is applicable to pontoon type floating roofs and pan type roofs and to side wall seals composed either of a single shoe that extends practically continuously around the tank side wall, or a side wall seal composed of a plurality of segmental-shaped shoe members whose ends are joined together by gas-tight, flexible connecting devices, or in any other suitable way, so as to produce a continuous, or substantially continuous, annular member arranged inside of the'tank in approximately parallel relation with the'side wall of the tank and having sufficient circumferential flexibility to enable said annular member to conform, or approximately conform, to the shape "or curvature of the tank side wall; The pusher mechanism herein illustrated and described is similar to the pusher mechanism de-' scribed in my prior patent previously mentioned, in that it comprises a plurality of spring-pressed actuating devices rockably mounted on the peripheral portion of the floating roof and projecting downwardly into a sealed gas space located between the tank side wall and the float ing roof, and presser bars operatively connected with the lower' end portions of said actuating devices and arranged so that they will engage or bear upon the inner side of the annular side wall seal at a point intermediate the top and bottom edges of said seal, and exert outward pressure on said side wall seal in a directionfto hold the same against the tank side wall. It difiers from the presser mechanism disclosed in my said patent f ('1) In the way the rockable actuating devices aremounted on the roof;

(2) In the means employed for applyingthe pressure of said actuating devices to the side wall seal; and

'(3) In the means employed to seal the openings in the floating roof, in which the rockable actuating devices are positioned and which provide for the rocking movement of said actuating devices relatively to the roof. One outstanding difference between the'presser mechanism that iormsthe subject-matter of my present application and the presser mechanism disclosed in my said prior patent, is that my present mechanism comprises spring-actuated, rockable actuating devices for the presser bars, so constructed and arranged that the thrust produced by the presser barson the side wall seal has no tendencyt'o' cause said side wall seal "to move circumferen tially away from the position said side wall seal naturally assumes. This is advantageous, in that it overcomes the necessity of arranging the presser bar actuating devices in two groups, one of which groups tends to move the side wall seal circumferentially to the right, and the other group tending to move the side wall seal circumferentially to the left, as described in said patent.

Referrin to the accompanying drawings, which illustrate the preferred form of my invention, A designates the side wall of a tank in which liquid is adapted to be stored, B designates a roof that floats upon the liquid in said tank, C designates an annular-shaped side wall seal arranged in sliding engagement with the inner face of the tank side wall A, and D designates a flexible sealing device, usually constructed from a piece of gas-tight fabric attached in any suitable way to the upper end portion of the side wall shoe C and to the peripheral portion of the floating roof -B, so as to form a gas-tight closure for the gas space between the side wall seal C and the floating roof. The sidewall seal may be mounted on the roof in various ways. Preferably, the floating roof B is provided with spring-actuated, rockable hangers C, from which the seal C is suspended by swinging links C that provide for a limited circumferential movement of the seal C relative to'the floating roof, as explained in my prior U. S. Patent No. 2,287,211.

My improved presser mechanism comprises a plurality of horizontally-disposed presser bars E, arranged in spaced relation around the circumference of the roof in the space between the roof and the side wall seal C, actuating devices for said presser bars, formed by vertically-disposed levers F that are connected by universal joints with the peripheral portion of the roof B, and tension springs or an equivalent means G, attached to the top side of the roof and to the upper end portions of the actuating levers F for exerting pressure on said levers F, so as to cause said tension springs, levers and presser bars to co-act with each other to produce a structure that holds the seal C in sliding engagement with the tank side wall without tending to move said .seal circumferentially, but which, in the event that said seal does move circumferentially either to the right or to the left, creates force that restores the seal C to the position at which it was originally set.

The actuating levers F are disposed vertically and are arranged so as to rock about horizontal axes. Preferably, each of the levers F is disposed in an upright position in a tubular member or attached in a gas-tight manner to a collar I horizontally-disposed flange 2 that .projects laterally from the roof and constitutes the peripheral portion of the top side of the roof. The collar l is provided with a horizontally-disposed pivot or pintle pin 3 that is positioned in hole 4 in the lever F which is of considerable greater diameter than the diameter of the pivot :pin .3 (see Figure 4). The above described structure produces a universal joint between the lever F and the floating roof, that permits said lever to rock radially of the roof and also swing laterally to the right a minimum distance .of approximately .3 inches and also swing laterally to the left a minimum distance of approximately 3 inches, out of the vertical plane in which said lever F normally lies. Each of the levers or actuating devices F has its lower endiportion connected by a universal joint or universal connection with a presser bar E, which .bar may be conveniently formed from a piece of angle iron. The presser bar E is disposed horizontally, and it is provided at its opposite ends with rockable bearing members 5 that are attached to the presser bar by vertically-disposed pivots 6. This form of construction is desirable, in that it causes the outward thrust produced by the presser bar on the side wall seal C to be applied evenly to said seal, andto be distributed uniformly over a relatively" great area of said side wall seal. If desired, the bearing members 5 may be provided at their opposite ends with vertically-disposed contact pieces 1 having convexed surfaces that are in sliding engagement with the side wall seal C, and hence, provide for relative circumferential movement between said seal C and the presser bar E.

The above mentioned universal joint or universalconnection between each presser bar E and the lower end portion of its co-acting lever or rockable actuating device F, permits the presser bar to remain in a level or horizontal position, free from strains tending to .tilt or tip it when the actuating lever F rocks'inwardly and outwardly towards and away from the tank side wall, as indicated by the full and broken line in Figure 5. In the form of my invention herein illustrated, the universal joint at the lower end of each lever F comprises a pair of angularlydisposed, rigid pins 8 that project forwardly from the front side of said lever into holes 9 in the depending vertical flange of the presser bar B, said holes 9 being of greater diameter than the diameter of the pins 8, so as to permit the presser bar to have limited universal movement relatively to the lever or movement in a plurality of different directions. If desired, the pins 8 may be provided with upturned or hook-shaped end portions B that tend to prevent said pins from withdrawing from the holes 9 when the lower end portion of the lever F swings inwardly or to the right, looking at Figure 5. At a point directly above the pins 8, a horizontally-disposed, convex-shaped bearing piece it is attached to the front side of the actuating lever F, said bearing member In being conveniently formed from a piece of round metal bar.

Any suitable means may be used to seal the collars or vertically-disposed, tubular parts i on the peripheral portion of the roof, in which the actuating levers F are mounted, and up through which said levers extend. I prefer, however, to use flexible boots H that are attached by wire clamps 1.2, or any other suitable means, to the levers F and to the collars l which said boots surround. The above construction produces inexpensive, gas-tight connections between the actuating levers F and the deck of the floating .roof, which allows said levers to move in all directions relative to the roof.

Normally, the presser bars E and the bearing members 5 on same .are held in proper relationship with the actuating levers F by (friction, resulting from the pressure of the lower end portions of the levers F against the depending .vertical flanges of the presser bars E, caused by the tension of the springs G attached to the upper ends of the levers F. As previously explained, the holes9 in thepresser bars which receive the forwardly-projecting pins 8 on the lowerends'of the levers F, are much larger than the pins 8, .so that circumferential or sidewise movement-of the presser bars, of a limited scope, canoccur at this point. sidewise ior circumferential movement of the presser barsmay be caused by .the side wall seal C moving circumferentially relative to the floating roof, due to the tank side wall A bein out of round at various points in its height. This relative circumferential movement is a maximum of about four inches. Hence, the allowance for angular movement need not be great. Pivoting between the actuating levers F and presser bars E for rotary movement, is attained by the pins 8 at the lower ends of said levers sliding in and out of large holes 9 in the presser bars E. The amount of this movement is about 11 inches. Part of the time the convened bearing members at the lower ends of the actuating levers F receive the load between the levers F and the depending flanges of the presser bars E. The convexed bearing members 10 are employed so that the pins 8 will not tend to bind in the holes 9 in the presser bars when the side wall seal 0 moves into close proximity to the floating roof.

In Figure 2 of the drawings the broken lines represent the center line of each actuating lever F and its operating spring G, in instances Where the side Wall seal C has moved circumferentially to the left from its normal position. It can be seen that the tension of the spring G has a horizontal component which tends to pull the upper end of the lever F to the left, which hence tends to pull the lower end portion of the lever to the right. Thus, through friction of the contact pieces 7 of the pivoted bearing members 5 on the presser bars E against the side wall seal C, there is a pull on said seal C towards the right which tends to bring said seal C back to its original position relative to the floating roof, as shown in solid lines in Figure 2.

From the foregoing, it will be seen that my new combination consisting of (a) Levers F joined to the roof by universal connections which permit said levers to rock inwardly and outwardly relatively to the side wall seal C and also move circumferentially a minimum distance of approximately 3 inches to the right and of approximately 3 inches to the left;

(1)) Presser bars E joined by universal connections with the lower ends of said levers;

(c) Rockable bearing members 5 on said presser bars;

(d) Contact pieces 1 on the bearing members 5 provided with convexed surfaces that are in sliding engagement with the side Wall seal C; and

(e) A spring G attached to each of said levers so as to normally hold the lever in a true radius of the tank roof, produces a structure that holds the seal C in engagement with the tank wall without tending to move said seal circumferentially, and which, in the event of circumferential movement of the seal C to the right or left, a minimum distance of approximately 3 inches in each direction, creates a force that automatically restores the seal C to the position in which it was originally set.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is: i

1. The combination of a liquid storage tank provided with a side wall, a roof for said tank that floats on the liquid in the tank, an annular side wall seal surrounding said roof and arranged in opposed relation to the tank side wall with the lower edge portion of said seal submerged in the liquid on which the roof floats, mechanism carried by the roof for supporting said seal and providing for a limited circumferential movement of the seal relatively to the roof, a flexible element secured to the roof and conneoted. to the side wall seal so as to form a closure for an annular vapor space at the peripheral edge of the roof, presser devices in said vapor space consisting of horizontally-disposed, barlike elements provided at their opposite ends with pivotally mounted bearing members that are in sliding engagement with the inner face of said side wall seal, actuating levers joined by universal connections with said presser devices, universal connections between the roof and said levers having provision for permitting said levers to rock laterally to the right a minimum distance of approximately three inches and rock laterally to the left a minimum distance of approximately three inches in the event said side wall seal moves circumferentially relatively to the roof, and a means that causes said actuating levers to exert a radial outward thrust on said presser devices and also counteract tendency of said levers to rock laterally to the right and to the left, as above mentioned.

2. The combination of a liquid storage tank provided with a side wall, a roof for said tank that floats on the liquid in the tank, an annular side wall seal surrounding said roof and arranged in opposed relation to the tank side wall with the lower edge portion of said seal submerged in the liquid on which the roof floats, mechanism carried by the roof for supporting said seal and providing for a limited circumferential movement of the seal relatively to the roof, a flexible element secured to the roof and connected to the side wall seal so as to form a closure for an annular vapor space at the peripheral edge of the roof, presser devices in said vapor space formed by horizontally-disposed, bar-like members provided with pivotally-mounted parts havin vertically-disposed contact pieces that have convexed surfaces which are in sliding engagement with said side wall seal, actuating levers pivotally attached at their lower ends to said presser devices, universal connections between the roof and said levers having provision for permitting said levers to rock laterally to the right a minimum distance of approximately three inches and rock laterally to the left a minimum distance of approximately three inches in the event said side wall seal moves circumferentially relatively to the roof, and a means for causing said actuating levers to exert a radial outward thrust on said presser devices and also counteract tendency of said levers to rock laterally to the right and to the left, as above mentioned.

JOHN H. WIGGINS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,580,194 Glass Apr. 13, 1926 1,662,225 Wiggins Mar. 13, 1928 1,894,635 Santos Jan. 17, 1933 1,930,953 Hampton Oct. 17, 1933 2,180,587 Hammeren Nov. 21, 1939 2,287,211 Wiggins June 23, 1942 2,302,904 Wiggins Nov. 24, 1942, 2,313,856 Wiggins Mar. 16, 1943 FOREIGN PATENTS Number Country Date 80,679 Sweden Apr. 19, 1934 549,419 Germany Apr. 27, 1932 

